US3602800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coupler for interconnecting customer equipment with telephone network
Assignee: AT&T Inc
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Filing: 1969-05-21
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Granted: 1971-08-31
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Expires: 1989-05-21
Abstract
Abstract A coupler for attaching customer-owned equipment to the telephone network permits any customer signal below a prescribed signal level to pass without distortion or attenuation but linearly attenuates signals exceeding the prescribed level. The coupler measures the mean power of the customer''s signal and utilizes the results to switch the proper attenuating load across the line. The switch circuit of the coupler has a hysteresis characteristic to prevent distortion of the customer''s signal by repeated switching between different alternating modes when the customer''s signal has slight variations about the prescribed threshold level.
Inventors
- 👤 David Feldman
- 👤 John J Golembeski
- 👤 Tadikonda N Rao
- 👤 Ralph W Wyndrum Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:08
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/005
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
78 words
Circuit means for controlling the mean power level of a signal coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential whereby the level of said signal is controlled.
Claim 2
Dependent Claim
78 words
Circuit means for controlling the mean power level of a signal coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential whereby the level of said signal is controlled.
Claim 3
Dependent Claim
98 words
Circuit means for controlling the level of a signal coupled to aN input terminal of a second circuit means, comprising, in combination, first and second transistors differentially connected so that the potential difference between the collector terminals of said first and second transistors is a measure of the mean power of said signal, amplifier means responsive to said first and second transistors, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential whereby the level of said signal is controlled.
Claim 4
Dependent Claim
98 words
Circuit means for controlling the level of a signal coupled to aN input terminal of a second circuit means, comprising, in combination, first and second transistors differentially connected so that the potential difference between the collector terminals of said first and second transistors is a measure of the mean power of said signal, amplifier means responsive to said first and second transistors, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential whereby the level of said signal is controlled.
Claim 5
Dependent Claim
15 words
Apparatus in accordance with claim 2 including a capacitive element connected between said collector terminals.
Claim 6
Dependent Claim
82 words
Apparatus in accordance with claim 2 including means for biasing said first and second transistors comprising first and second current sources connected to said collector terminals of said first and second transistors, respectively, means for connecting the emitter terminals of said first and second transistors, a third current source connected to said connecting means, and means for controlling said first, second and third current sources, whereby a differential output can be obtained from said collector terminals of said first and second transistors.
Claim 7
Dependent Claim
35 words
Apparatus in accordance with claim 4 wherein said first and second current sources comprise, respectively, third and fourth transistors having matched characteristics and said third current source comprises fifth and sixth transistors having matched characteristics.
Claim 8
Dependent Claim
46 words
Apparatus in accordance with claim 5 wherein said control means comprises seventh and eighth transistors, said seventh transistor having characteristics matched with said characteristics of said third and fourth transistors, and said eighth transistor having characteristics matched with said characteristics of said fifth and sixth transistors.
Claim 9
Dependent Claim
34 words
Apparatus in accordance with claim 6 further including means for ensuring that all of the currents flowing through the emitter electrodes and through the collector electrodes of all of said transistor are substantially equal.
Claim 10
Dependent Claim
109 words
Circuit means for controlling the level of a signal coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, said amplifier means including first and second transistors differentially connected so that the potential at the collector terminal of said second transistor is a measure of the mean power level of said signal, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential whereby the level of said signal is controlled.
Claim 11
Dependent Claim
109 words
Circuit means for controlling the level of a signal coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, said amplifier means including first and second transistors differentially connected so that the potential at the collector terminal of said second transistor is a measure of the mean power level of said signal, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential whereby the level of said signal is controlled.
Claim 12
Dependent Claim
79 words
Apparatus in accordance with claim 8 including means for biasing said first and second transistors comprising first and second current sources connected to the collector terminals of said first and second transistors, respectively, means for connecting the emitter terminals of said first and second transistors, a third current source connected to said connecting means, and means for controlling said first, second and third current sources, whereby a single output may be taken from the collector of said second transistor.
Claim 13
Dependent Claim
36 words
Apparatus in accordance with claim 9 wherein said first and second current sources comprise, respectively, third and fourth transistors, said third current source comprises fifth and sixth transistors, and said control means comprises a seventh transistor.
Claim 14
Dependent Claim
53 words
Apparatus in accordance with claim 8 including means for biasing said transistors whereby said switch means exhibits a hysteresis characteristic in that the voltage potential required at said base electrode of said second transistor to initiate conduction in said second transistor is substantially greater than the said potential required to maintain said conduction.
Claim 15
Dependent Claim
144 words
Circuit means for controlling the level of a signaL coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential, said switch means including first and second transistors, first means connecting the emitter terminals of said first and second transistors, and second means connecting the collector electrode of said first transistor to the base electrode of said second transistor so that said second transistor is caused to conduct and connect said load means between said input terminal and said reference potential when said first transistor is not conducting whereby the level of said signal is controlled.
Claim 16
Dependent Claim
144 words
Circuit means for controlling the level of a signaL coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, load means, and switch means responsive to said amplifier means for connecting said load means between said input terminal of said second circuit means and a reference potential, said switch means including first and second transistors, first means connecting the emitter terminals of said first and second transistors, and second means connecting the collector electrode of said first transistor to the base electrode of said second transistor so that said second transistor is caused to conduct and connect said load means between said input terminal and said reference potential when said first transistor is not conducting whereby the level of said signal is controlled.
Claim 17
Dependent Claim
22 words
Apparatus in accordance with claim 12 wherein said load means comprises a resistor connected between said first means and said reference potential.
Claim 18
Dependent Claim
114 words
Circuit means for controlling the level of a signal coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, load means including a multiple of load devices, and switch means responsive to said amplifier means, said switch means comprising a multiple of switch circuits each of which is associated with a respective one of said load devices, said switch circuits operating sequentially to connect said respective load devices between said input terminal and a reference potential as said signal exceeds a sequence of preselected thresholds whereby said level of said signal is controlled.
Claim 19
Dependent Claim
114 words
Circuit means for controlling the level of a signal coupled to an input terminal of a second circuit means, comprising, in combination, detection means for measuring the mean power level of said signal, amplifier means responsive to said detection means, load means including a multiple of load devices, and switch means responsive to said amplifier means, said switch means comprising a multiple of switch circuits each of which is associated with a respective one of said load devices, said switch circuits operating sequentially to connect said respective load devices between said input terminal and a reference potential as said signal exceeds a sequence of preselected thresholds whereby said level of said signal is controlled.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-30 | 1975-03-01 | 1975-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-30 | 1979-03-01 | 1979-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-30 | 1983-03-01 | 1983-08-31 | $7700.00 | Window Closed / Lapsed |